The invention relates to printing composite images that can contain large amounts of information, optionally including redundant information, in an eye-pleasing format. The composite image provides high information density in a highly reliable and visually pleasing form and has significant security features. The composite images are achieved with a novel arrangement of largely invisible, machine-readable postage evidencing information, e.g., Information Based Indicia (IBI) images containing 2-D bar code information, and dark, visible images containing human-readable postage information, which typically includes address information. The images can be printed using conventional ink jet printers.
Postage evidencing information, including IBI images, is a significant feature of the Information-Based Indicia Program (IBIP) implemented by the United States Postal Service (USPS) as a distributed trusted system. The IBIP includes open IBI postage evidencing systems, which can apply postage in addition to performing other functions not possible with conventional postage machines. The IBIP requires printing high density, two-dimensional (2-D) bar codes, such as PDF417 bar codes, on mailpieces. The requirements for printing a PDF417 2-D bar code are set forth in The Uniform Symbology Specification. The Postal Service expects the IBIP to provide cost-effective assurance of postage payment for each mailpiece processed. IBI images comprise certain human readable information and two-dimensional (2-D) bar code information, which can contain such assurance. However, printed information is often obscured, diminishing its reliability even with error correction technology. There is a need for a high-density image format that includes both human readable and bar code information with high reliability.
The USPS has published specifications for the IBIP such as PERFORMANCE CRITERIA FOR INFORMATION-BASED INDICIA AND SECURITY ARCHITECTURE FOR OPEN IBI POSTAGE EVIDENCING SYSTEMS (PCIBI-O), dated Jan. 12, 1999; PERFORMANCE CRITERIA FOR INFORMATION-BASED INDICIA AND SECURITY ARCHITECTURE FOR CLOSED IBI POSTAGE METERING SYSTEMS (PCIBI-C), dated Feb. 23, 2000; and PERFORMANCE CRITERIA FOR INFORMATION-BASED INDICIA PROGRAM (IBIP) SYSTEMS EMPLOYING CENTRALIZED POSTAL SECURITY DEVICES, dated Aug. 17, 2000; (collectively referred to herein as the “IBIP Specifications”). The IBIP includes interfacing user (customer), postal and vendor infrastructures, which are the system elements of the program. The term “postage evidencing information” is meant to include IBI images meeting the current IBIP Specifications as well as alternative formats.
A user infrastructure, which typically resides at the user's site, can comprise a postage security device (PSD) coupled to a host system. The PSD is a secure processor-based accounting device that dispenses and accounts for postal value stored therein. The host system (Host) may be a personal computer (PC) or a meter-based host processor. Alternatively, the PSD can be located on a server remote from the user. Wherever the PSD is located, it would be desirable for IBIP indicium to be printed using an open system comprised of conventional desk-top and other ink jet printers not dedicated to postage, but this capability has not been fully realized without sacrificing readability or the visual appearance of the printed mailpiece.
The IBIP Specifications require a minimum bar code read rate of 99.5% and place the responsibility on each IBIP vendor to meet this requirement. One of the issues raised is the readability of 2-D bar codes printed on envelopes. Different printing technologies work well with different types of paper. One particularly bad combination is ink jet printing on porous paper, such as recycled paper. The ink spots tend to feather, reducing the resolution and quality of the print. Thus, there is concern over the quality of postage evidencing symbology, such as 2-D bar codes, printed by ink-jet printers. Because the 2-D bar code comprises a lot of information, the quality of the print has a direct effect on the readability of the bar code. Furthermore, the print quality is affected by various printer characteristics that may be specific to each individual printer. In particular, since PC meter printers are open and not dedicated to printing postage indicia, they are not expected to meet any USPS requirements, such as the minimum read rate set forth in the IBIP Indicium Specification. A number of other factors, such as environmental conditions, type of ink and printer wear, can also affect print quality. Thus, the readability of the 2-D bar code will be affected by the various conditions outside the control of an IBIP vendor.
Adding another level of complexity, current United States Postal Service IBI specifications require a Facing Identification Mark (FIM) to be part of the IBI image so that the USPS Advanced Facer Canceller may detect the presence of an IBI mailpiece so as to sort the mailpiece properly. In the United States, the FIM is a pattern of vertical bars printed in the upper right portion of the mailpiece, to the left of the indicia. As currently specified, the United States Postal Service FIM is large, taking up approximately 20% of the proposed IBI image. A FIM uses a large amount of envelope space, which restricts the amount of information that can conveniently and neatly be presented in the IBI image. It would be desirable to eliminate the need for an FIM, such as through the use of fluorescence at the correct wavelength for reading by a facer-cancelor.
Security is a significant consideration for IBI indicia but machine-readable invisible ink has not been used for this purpose. Using current technology, invisible inks cannot be printed reliably without taking into account and adjusting for envelope material. Therefore, although 2-D bar codes are widely used to determine mail code authentication, useful 2-D bar codes are visible and can detract from the appearance of a mailpiece. Invisible inks have been available for a variety of uses and have been used in combinations with inks visible to the human eye, including for IBI images. Unfortunately, there are limitations as to current printing devices and inks, including invisible inks that can be used in ink jet printing devices. Low viscosity ink jet inks provide poor image resolution on porous paper, making the printing of a composite visible-invisible image problematic in an ordinary two cartridge ink jet printer having one black cartridge and one color cartridge with multiple, e.g., three, color nozzles. A three-nozzle, color cartridge cannot provide a dark enough image to meet IBI readability (machine reading) rates.
The need for high resolution has posed significant technical challenges, even with single-ink systems, due to paper and ink variations. Print quality for IBI images is essential, and in U.S. Pat. No. 5,871,288, Ryan, Jr., et al., describe a method for customer selectable module size for an information based indicia to assure quality for a 2-D bar code. Their method includes determining printer type, including print resolution, for printers that will print 2-D bar code and entering paper type for the envelope. Then, a suggested 2-D bar code module size is calculated based on the paper and the printer type. A test sample 2-D bar code is printed at the suggested 2-D bar code module size. The printed test sample is scanned and then evaluated for print quality and readability. They do not address the problem of controlling visual clutter on a mailpiece and are also not concerned with composite visible-invisible images. It would be desirable to avoid the need for customer setup and still assure an adequate read rate on all media while providing a large amount of printed information with little visual clutter. Current systems cannot provide a suitable combination of convenience, acceptable appearance and high readability.
Some recent systems employ a plurality of inks. For example, two recent patents, U.S. Pat. Nos. 6,270,213 and 6,142,380 to Sansone, et al., describe the use of dual luminescent inks to produce a postal orienting and sorting identification mark for information-based indicia (IBI) that does not require an FIM and is able to be read by Advanced Facer Canceller Systems. These patents describe printing layered images on the mailpiece. In particular, an upper layer IBI indicia is printed over a lower layer invisible ink. The lower layer ink is described as a “dual luminescent ink” that is invisible to the naked eye and the upper layer IBI indicia is printed with an ink that is visible to the naked eye. The lower layer may also be produced by two inks, one of which is fluorescent and the other of which is phosphorescent. The fluorescent ink is printed in one area of the lower layer and the phosphorescent inks is printed in another area of the lower layer. This does not address the problems solved by the invention which enables printing highly-reliable, high-density composite images using conventional ink jet printers.
Some prior art has utilized invisible inks and visible inks useful in certain contexts. For example, in U.S. Pat. No. 5,502,304, Berson, et al., describe a system that employs upper and lower bar codes. The lower layer bar code is written on an object with a normal ink and an upper layer bar code is written over the lower layer bar code with an ink that is invisible to the naked eye. A detector apparatus is described that is able to read the upper and lower level bar codes. And, in U.S. Pat. No. 5,525,798, Berson, et al., describe inks that are selectively excitable by different wavelengths of incident radiation. These inks allow a lower layer bar code to be written on an object with an invisible ink and an upper layer bar code to be written over the lower layer bar code with an ink that is invisible to the naked eye. The basic problems of the present invention, are not, however, addressed.
In U.S. Pat. No. 5,693,693, to Auslander, et al., wax-based invisible inks are described that emit light at various wavelengths in the visible region when they are excited by UV light. This allows lower layer clear text information to be written on an object with a regular, visible ink and an upper layer bar code to be written over the lower layer text information with an ink that is invisible to the naked eye. In this manner, more information can be provided than with conventional bar codes. In U.S. Pat. No. 5,684,069, to Auslander, an invisible ink is described that utilizes a substituted phthalocyanine dye in combination with selected waxes and resins. The ink is useful in thermal printing. It is transparent or almost transparent in white light, but is responsive to infrared light in the range of 720 to 1000 nm. The preferred waxes are polyethylene wax, natural paraffin wax and carnauba wax, and the preferred resin is ethyl vinyl acetate polymer. The patent refers to a prior process for providing security by printing authenticating text in invisible ink so that the same does not interfere with the document upon which such text is printed, but enables determining the authenticity and the holder of the document. An example is a scheme for placing a transparent label over a document with text printed on the label in invisible ink so that text covered by the label can be read. Again, the concerns of the invention are not addressed.
A number of other patents describe invisible inks and their use for postal and other applications without addressing the concerns of the invention described in this application.
U.S. Pat. No. 5,542,971, to Auslander, et al., describes inks that are selectively excitable by different wavelengths of incident radiation. This allows a lower layer bar code to be written on an object with an ink and an upper layer bar code to be written over the lower layer bar code with an ink that is invisible to the naked eye. In this manner, the lower layer and upper layer bar code can contain more information than conventional bar codes. The invisible inks used are based on complexes of rare earth elements with an atomic number higher than 57 such as: Eu, Gd, Tb, Sm, Dy, Lu with various chelating agents providing chromophore ligands that absorb in the ultraviolet and the blue region of the spectra such as: β-diketones, dipicolinic acid, etc.
In U.S. Pat. No. 5,837,042, Lent, et al., describe invisible fluorescent jet inks said to be suitable for producing security markings on documents and other articles. The jet ink compositions comprise a fluorescent colorant, an ink carrier, and optionally one or more binder resins. The markings are invisible to the unaided eye and are visible only when excited by ultraviolet light. The colorant comprises a rare earth metal and a chelating ligand, is excitable by ultraviolet light having a wavelength of from about 275 nm to about 400 nm, and fluoresces at a wavelength of from about 550 nm to about 700 nm, with the proviso that when the rare earth metal is europium, dysprosium, or terbium, the chelating ligand is not dibenzoylmethane. Also described is a method of identifying objects comprising providing a security marking as described above, exciting the marking and reading the fluorescent emission.
In U.S. Pat. No. 6,149,719, Houle describes light sensitive invisible ink compositions and methods for using them. The disclosed system generates high-definition, lightfast images that are easily read or otherwise detected using far red, infrared, and/or ultraviolet light. The inks contain an uncomplexed invisible metal phthalocyanine far red/infrared fluorophore (optimally chloroaluminum [III] phthalocyanine tetrasulfonic acid or salts thereof). An ultraviolet fluorophore can also be included. The inks are invisible to the unaided eye, but when exposed to far red or infrared light (wavelength=about 650-715 nm) they fluoresce at a wavelength of about 670-720 nm. When an ultraviolet fluorophore is employed, the inks can also be detected by applying ultraviolet light (wavelength=about 250-380 nm) which results in fluorescent emission at a wavelength of about 400-650 nm. The inks are said suited for forming invisible images using inkjet technology.
In U.S. Pat. No. 5,929,415, Berson describes a postage metering refill system that utilizes information contained in information based indicia to audit the franking process. Specifically, he provides a system that scans and reads IBI in accordance with the USPS Specification. The system addresses both the readability and security of the IBI. The apparatus utilizes a postage meter that prints an IBI, scans and checks the IBI and prints an invisible, secure message, i.e., bar code, over the IBI. When, the mailpiece arrives at the post, the additional material is scanned and read at the same time the IBI information is scanned and read. The scanned verification information is then collected and may be subsequently transmitted to a central data center and used for further verification of the postage paid. This stored information may be retrieved during connection to a central postage meter resetting data center when the meter is reloaded and forensically checked.
In U.S. Pat. No. 6,039,257, Berson, et al., describe a system that utilizes a postage meter that prints an Information-Based Indicia, scans and checks the Information-Based Indicia and prints an invisible, secure message, i.e., bar code over the Information-Based Indicia.
There remains a need for a system that can produce machine-readable IBI images containing both 2-D bar code information and address and postage information that are printed to provide increased read rates and the provision of high information density without obscuring any one component. It would be desirable in this context to print an IBI image that would include redundant information within the IBI image or between the IBI and a visible dark image. It would be especially desirable to have such a system wherein the images are printed using conventional ink jet printers using water-based inks.